E8 High

Viessmann E8 Fault Code

The Viessmann E8 fault code means: your boiler is struggling to confirm that the internal flame has successfully ignited, so it has safely shut down to prevent gas buildup.. It appears on 3 Viessmann models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Ionisation current lies outside the permissible range
Typical repair cost £150-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Viessmann models that show the E8 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Viessmann E8 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026